1. Field of the Invention
This invention relates generally to microwave heating devices and specifically for such devices wherein the device may be used for drying materials containing water much faster than conventional heating structures particularly for use with laboratories and the like.
2. Description of the Prior Art
A common problem with known heating devices of conventional type is that when used for heating or drying laboratory samples a relatively long time period is required for achieving the desired result. Also, it is generally desirable in lab work to heat small samples with finely controlled analytical heating of such samples. However, known type heating devices to date have not been able to accomplish the results with the degree of accuracy, precision and predictability desired.
There have been devices made to heat by microwave technology, but often times they are still far from being completely effective. Often times, while the microwave-type heating device will speed up the overall heating process, control thereof is relatively inaccurate and unpredictable, and it is very difficult to repeat each of a plurality of tests with the same degree of precise control of the overall heating for each and every sample. In order to accomplish these desired results, new and novel structure for controlling the heating by microwaves is disclosed in this application.
Existing prior patents which may be pertinent to the present invention are as follows:
A patent to Kaminaka U.S. Pat. No. 4,236,055 discloses a microwave oven employing a Triac 18 in the power circuit for the magnetron. In addition, a cooling fan 10 remains energized after the magnetron is switched off to cool the high voltage transformer 7, the microprocessor 2, and the magnetron 9.
The patent to Stahl et al, U.S. Pat. No. 4,233,478, shows a temperature monitoring apparatus in a microwave-type oven.
The patent to Paglione U.S. Pat. No. 4,228,809 discloses another type of temperature controller for a microwave heating device.
U.S. Pat. Nos. 4,121,149; 4,223,195; 4,268,779; 4,314,197; and 4,323,861 all disclose various power control circuits in microwave ovens each of which includes a Triac.
However, none of the known prior art devices offer the new and novel features of the invention.